Build polygon areas from multiple linestrings

Constructs polygon or multipolygon geometries from a collection of linestrings, handling intersections and creating unified areas. Returns POLYGON or MULTIPOLYGON (not wrapped in a geometry collection). Requires MULTILINESTRING input - for single linestrings, use ddbs_make_polygon().

Usage

ddbs_build_area(
  x,
  conn = NULL,
  name = NULL,
  crs = NULL,
  crs_column = "crs_duckspatial",
  mode = NULL,
  overwrite = FALSE,
  quiet = FALSE
)

Arguments

x

Input spatial data. Can be:

A duckspatial_df object (lazy spatial data frame via dbplyr)
An sf object
A tbl_lazy from dbplyr
A character string naming a table/view in conn

Data is returned from this object.

conn

A connection object to a DuckDB database. If NULL, the function runs on a temporary DuckDB database.

name

A character string of length one specifying the name of the table, or a character string of length two specifying the schema and table names. If NULL (the default), the function returns the result as an sf object

crs

Deprecated The coordinates reference system of the data. Specify if the data doesn't have a crs_column, and you know the CRS.

crs_column

Deprecated a character string of length one specifying the column storing the CRS (created automatically by ddbs_write_vector). Set to NULL if absent.

mode

Character. Controls the return type. Options:

"duckspatial" (default): Lazy spatial data frame backed by dbplyr/DuckDB
"sf": Eagerly collected sf object (uses memory)

Can be set globally via ddbs_options(mode = "...") or per-function via this argument. Per-function overrides global setting.

overwrite

Boolean. whether to overwrite the existing table if it exists. Defaults to FALSE. This argument is ignored when name is NULL.

quiet

A logical value. If TRUE, suppresses any informational messages. Defaults to FALSE.

Value

Depends on the mode argument (or global preference set by ddbs_options):

duckspatial (default): A duckspatial_df (lazy spatial data frame) backed by dbplyr/DuckDB.
sf: An eagerly collected object in R memory, that will return the same data type as the sf equivalent (e.g. sf or units vector).

When name is provided, the result is also written as a table or view in DuckDB and the function returns TRUE (invisibly).

Usage

Arguments

Value

See also